The present invention relates to optical fibers, more specifically optical fibers which include a data storage medium capable of being digitally encoded (or digitally encoded) with a data signal, as well as methods of making and using the same.
Optical fibers, including fiber optic ribbons, have acquired an increasingly important role in the field of communications, frequently replacing existing copper wires. This trend has had a significant impact in the local area networks (e.g., for fiber-to-home uses), which have seen a vast increase in the usage of optical fibers. Further increases in the use of optical fibers in local loop telephone and cable TV service are expected, as local fiber networks are established to deliver ever greater volumes of information in the form of data, audio, and video signals to residential and commercial users. In addition, use of optical fibers in home and commercial business for internal data, voice, and video communications has begun and is expected to increase.
A typical geometry for an optical fiber 10 is illustrated in FIG. 1, where the optical fiber contains a cylindrical core 12 at the center of the fiber, a cylindrical clad 14 surrounding the core, a primary or inner coating 16 which surrounds the clad, and a secondary or outer coating 18 which surrounds the primary coating. The primary coating is applied directly to the glass fiber (e.g., core and clad) and, when cured, forms a soft, elastic, and compliant material which encapsulates the glass fiber. The primary coating serves as a buffer to cushion and protect the glass fiber when the fiber is bent, cabled, or spooled. The secondary coating is applied over the primary coating and functions as a tough, protective outer layer that prevents damage to the glass fiber during processing and use.
Optical fibers are commonly used as bundles of strands with multiple fibers in a strand. It is necessary to have a means of fiber identification so that one can identify the individual fibers at the termination of such a bundle for appropriate connection of the fibers in a photonic system. Typically, optical fibers are coded for identification by a colored ink or other coating on the fiber. For example, the secondary or outer coating 18 may contain one or more colorants or dyes. One problem with the use of colorants is that the amount of information they can convey is quite limited. Moreover, the ability of the colorant to convey the necessary information is dependent upon proper identification of colors by a person working with such fibers. Fiber identification may be problematic under certain lighting conditions, where similar colorants are used on two different fibers (i.e., red versus orange), or where the colorants fade or otherwise change over time or following environmental exposure. Thus, the use of colorants is, by its very nature, of limited utility and subject to errant identification.
The present invention is directed to overcoming these deficiencies in the art.
One aspect of the present invention relates to an optical fiber including a fiber core and at least one coating substantially encapsulating the fiber core, wherein the at least one coating includes a material forming a data storage medium which is capable of digitally encoding information at a data density of at least about 4 bits per centimeter. Also disclosed are fiber bundles including one or more optical fibers of the present invention and cables including either an optical fiber of the present invention or a fiber bundle of the present invention.
Another aspect of the present invention relates to a method of making an optical fiber of the present invention. This method includes providing a fiber core and encapsulating the fiber core with a coating which includes a material forming a data storage medium capable of digitally encoding information.
A further aspect of the present invention relates to a method of digitally encoding information onto an optical fiber. This method includes preparing an optical fiber which includes a fiber core and at least one coating substantially encapsulating the fiber core, wherein the at least one coating includes a material forming a magnetic data storage medium, and exposing the optical fiber to a variable magnetic field under conditions effective to encode information onto the magnetic data storage medium.
A still further aspect of the present invention relates to another method of digitally encoding information onto an optical fiber. This method includes preparing an optical fiber which includes a fiber core and at least one coating including a material forming an optical data storage medium, and treating the optical fiber under conditions effective to encode information into the optical data storage medium.
Yet another aspect of the present invention relates to a method of retrieving information digitally encoded onto an optical fiber. This method includes providing an optical fiber including at least one coating which includes a material forming a digital data storage medium, the digital data storage medium being encoded with a data signal which carries information, and reading the optical fiber with a device which detects and processes the data signal, thereby retrieving the information.
By providing optical fibers with a coating that contains a material forming a digital data storage medium, it becomes possible to encode a data signal onto a length of fiber. This offers a significant advance over previously used dyes or colorants that were incorporated into the coating layer(s) of an optical fiber. Specifically, the data signal utilized in the present invention can encode much more information, both in complexity and volume, than previously utilized dyes and other colorants. For example, it becomes possible to indicate the product type (e.g., type of glass fiber, including core and clad) and production lot, attenuation properties, polarization mode dispersion, effective area, fiber certification standards, etc. Fibers could also be encoded with data regarding specific information concerning the particular application in which the fiber is employed, such as fiber installation, signal source, etc. Encoded data can also be utilized for manufacture and handling purposes. To convey more detailed information, the inventive articles may be encoded in more complicated patterns, as found in bar codes, credit card strips, or magnetic tape recordings.